CHEM 120 FINAL EXAM CHEM120 WEEK 8 FINAL EXAM

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CHEM 120 FINAL EXAM /CHEM120 WEEK 8 FINAL EXAM

LATEST ACTUAL EXAM - AND

CORRECT DETAILED ANSWERS|AGRA DE

The heat of fusion of water at 0 C is 334 Joules/gram. How many joules of energy would need to be removed from 2 moles of water at 0 C to convert it into ice at 0 C? Ans: 12.0 kJ.Question 26. Concentrated hydrochloric acid has a density of 1.19 g/mL and a concentration of 38% by mass. What is the molarity of acid in the solution?

A. 1.041 M

B. 12.4 M

C. 17 M

D. 0.23 M

E None of the above.

Question . What is the molality of a 2.30 M solution of sodium nitrate whose density is 1.08 g/mL?

• 3.2 m
• 2.6 m
• 2.3 m
• 0.0023 m

E 0.0026 m

Question . What is the vapor pressure at 50 C of a solution consisting of 70.7 g hexane and 0.100 moles of a nonvolatile solute? The vapor pressure of pure hexane (C6H14) at 50 C is 399 mm Hg.

• 0.057 atm
• 0.525 atm
• 546 atm
• 355 atm
• 0.468 atm

Question . How many moles of CO2 are in 2.8 liters of sparking water that was prepared at a pressure of 4.2 atm (25 C). The density of the solution is 1.20 g/mL.

• 0.486 moles
• 0.405 moles
• 0.400 moles
• 0.338 moles
• 0.145 moles

Question. What mass of glucose (C6H12O6), a molecule that does not break into particles, must be dissolved in 750.0 g water to give a solution with a boiling point of 101.50 C?

• 26,760 g
• 395 g
• 26.7 g
• 2.9 g
• 2.2 g
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Question . A 550 mL aqueous solution containing 600 mg of bovine insulin (a protein, not ionized) has an osmotic pressure of 6.7 mm Hg at 37 C. What is the molecular weight of insulin? 2 / 3

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• 4.1 g/mol
• 600 g/mol
• 3140 g/mol
• 23,000 g/mol
• 3.0x10

6 g/mol

What mass of glycerin (C3H8O3), a molecule that does not break into particles, must be dissolved in 200.0 g water to give a solution with a freezing point of -2.50 C?

• 0.269 g
• 1.34 g
• 13.7 g
• 24.7 g
• 123.6 g

Concentrated nitric acid has a density of 1.42 g/mL and a concentration of 16 M. What is the percent acid by weight in the solution?

A. 18%

B. 38%

C. 79%

D. 99%

E None of the above.

Question 12. A solution of phosphoric acid was made by dissolving 10.0 g H3PO4 in 100.0 mL water. The resulting volume was 104 mL. Calculate the mole fraction of phosphoric acid in the solution. Water has a density of 0.997 g/mL.

A. 0.0181

• 0.981 moles/L

C. 0.0148

• 1.02 moles/Kg

E. 0.1020

Question 13. What is the vapor pressure at 60 C of a solution consisting of 60.5 g pentane and 0.200 moles of a nonvolatile solute? The vapor pressure of pure pentane (C5H12) at 60 C is 457 mm Hg.

• 0.116 atm
• 0.525 atm
• 146 atm
• 369 atm
• 0.486 atm

Question 14. Estimate the boiling point of a 0.35 m aqueous solution of CaCl2.

A. 100.54 C

B. 99.46 C

C. 100.18 C

D 99.82 C

E 100.36 C

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